Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but is has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. Treatment of wounds with reduced pressure may be commonly referred to as “reduced-pressure wound therapy,” but is also known by other names, including “negative-pressure therapy,” “negative pressure wound therapy,” and “vacuum therapy,” for example. Reduced-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro-deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.
While the clinical benefits of reduced-pressure therapy are widely known, the cost and complexity of reduced-pressure therapy can be a limiting factor in its application, and the development and operation of reduced-pressure systems, components, and processes continues to present significant challenges to manufacturers, healthcare providers, and patients. One of the common challenges involves the use of batteries for portable reduced-pressure systems. Although a device may use a standard battery size such as, for example, an AA cell or a rechargeable pack, a user or caregiver may select batteries having different cell chemistries that may affect the operation of the portable reduced-pressure device. The batteries may be primary cells such as, for example, alkaline or zinc carbon cells, or rechargeable batteries such as nickel-cadmium or lithium-ion batteries. Different battery chemistries are used to suit different applications such as those that provide for recharging or offer a higher performance profile. Although a reduced-pressure system may be optimized to work with one particular type of battery, there is a danger that a user or caregiver may not follow directions and insert the wrong type of battery that causes the reduced-pressure system to function improperly during the treatment of a patient. Even when a reduced-pressure system might be capable of operating when a different battery type is used, the system might have a lower performance that would be optimized if the correct battery were used.
Another common challenge when using batteries is how to provide a reliable method for “fuel gauging” or for determining the remaining charge in a battery. As different battery types have different discharge curves and different initial voltages, this task is often simplified to nothing more than to provide an alert when the voltage drops to a predetermined level when the battery is nearly completely discharged and needs to be recharged or replaced. For example, devices configured to utilize current embodiments of fuel gauging often have a voltage that reads close to 100% until the batteries are already 90% discharged.
In order to make such portable reduced-pressure systems powered by batteries more reliable and predictable, and to accommodate different battery chemistries in the same system, a simple and effective method for identifying the cell chemistry of a battery installed in a device is desirable to better control and operate electrical devices including reduced-pressure systems utilizing batteries. A method for enabling the devices to alter their characteristics to accommodate the batteries installed without negatively affecting the performance of the reduced-pressure system is also desirable to provide seamless reduced-pressure treatment to a patient.